This invention relates to a spark gap device which is adapted so that when an overvoltage above a predetermined value is applied to a contact of a cathode ray tube socket, it is dissipated to ground to protect circuits connected to the socket from the overvoltage.
A cathode ray tube socket having this kind of spark gap device is disclosed, for example, in U.S. Pat. No. 3,251,016. In this patent, one conductor ring is incorporated in a certain spaced relation to a plurality of contacts housed in a socket and spark gaps are formed between the conductor ring and the contacts. In this conventional spark gap device, during assembling of the socket, there is the likelihood that the spacing between the contacts and the conductor ring changes to cause variations in the spark gaps, resulting in the defect of inaccurate protecting operation. Especially when the cathode ray tube sockets of this kind are mass-produced, variations in part accuracy and assembling state are liable to lead to variations in the spark gaps, so that a spark gap device with high accuracy cannot be mass-produced.
For example, in a cathode ray tube socket disclosed in Simovits et al U.S. Pat. No. 3,636,412, issued January 18, 1972, for "Tube Socket Assembly" a pattern for forming spark gaps is obtained by punching a piece of sheet metal and fixing it to an insulating substrate forming one part of the body of the socket, and then cutting or punching at required positions to form the spark gaps. In this case, the spark gaps are higher in accuracy than those in the case of the abovesaid U.S. Pat. No. 3,251,016, but since the spark gaps are formed by cutting or punching after the pattern for the spark gaps is fixed to the insulating substrate and shaped to be housed in the socket, the cutting or punching operation is hard to perform, making it difficult to obtain accurate spark gaps.
An object of this invention is to provide a spark gap device for cathode ray tube sockets which is highly accurate and ensures a protecting operation.
Another object of this invention is to provide a spark gap device for cathode ray tube sockets which is easy to manufacture and assemble and is especially suitable for mass-production.
Still another object of this invention is to provide a spark gap device for cathode ray tube sockets which ensures a protecting operation even in the case of a small socket and is easy to manufacture and assemble.